Digital Production Services Homepage Brown University Library Homepage Brown University Homepage

c u r i o

Imaging rare, unusual, and intriguing objects at the Brown University Library

Tag Archives: clipping paths

Coffee Pots and Clipping Paths

October 25, 2012 by | Comments Off on Coffee Pots and Clipping Paths

In addition to photographing Special Collections materials for ongoing digital projects, or for patron requests for publication, Digital Production Services also digitizes items to be featured in library-produced promotional publications. In 2008, a coffee pot once owned by “Dr. Bob” (Rober Holbrook Smith), a founder of Alcoholics Anonymous, was taken off the shelf and set against a simple white background to be photographed.

The photograph itself is a straightforward shot — at the time, captured using the John Hay Library’s Nikon Digital SLR camera. However, to remove the background for a publication layout, “clipping paths” were created in Adobe Photoshop. Clipping paths are a useful way to mask-out the background within a scene — in other words, clipping paths can be used to visually define the edge of an irregularly-shaped object which does not conform to a standard rectangle-based crop.


Above, L–R: detail of coffee pot digital image; detail of image with background removed via pixel-based selection; detail of image showing vector-based clipping path overlaying pixel grid; clipping-path-masked image as placed in final layout.

There are pixel-based methods of creating masks in Photoshop, although clipping paths offer a unique solution, storing resolution-independent Bézier-curved (vector-based) edges alongside the pixel-based image grid, particularly useful for layered layout designs. Curves used for clipping paths are the same vector-based curves now becoming more widely supported by web browsers, as part of the Scalable Vector Graphics (SVG) specification and HTML5’s <canvas> tag scripting. (For an example of resolution-independent, vector-based curves implemented solely via web-based technologies, see this proof-of-concept site by a Google employee.)